重力异常及其梯度张量DEXP定量解释方法的影响因素分析  

Influence factor analysis of quantitative interpretation for gravity anomaly and its gradient tensor by DEXP

作　　者：邱峰 杜劲松[1,2,3] 陈超 QIU Feng;DU Jin-Song;CHEN Chao(Institute of Geophysics and Geomatics,China University of Geosciences,Wuhan 430074,China;Hubei Subsurface Multi-scale Imaging Key Laboratory,China University of Geosciences,Wuhan 430074,China;State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)地球物理与空间信息学院,湖北武汉430074 [2]中国地质大学(武汉)地球内部多尺度成像湖北省重点实验室,湖北武汉430074 [3]中国地质大学(武汉)地质过程与矿产资源国家重点实验室,湖北武汉430074

出　　处：《物探与化探》2020年第3期540-549,共10页Geophysical and Geochemical Exploration

基　　金：中国地质调查局项目“东天山卡拉塔格—雅满苏一带戈壁荒漠浅覆盖区地质填图”(DD20179607);国家自然科学基金项目(41604060);国家重点研发计划“深海关键技术与装备”重点专项(2016YFC0303001-2);地质过程与矿产资源国家重点实验室自主研究课题(MSFGPMR01-4)。

摘　　要：快速成像反演方法是近几年重磁勘探定量解释的一个发展热点,由于其在计算过程中不需要加入先验信息,故而可以较为快速地估算场源的深度与密度等相关参量。DEXP(depth from extreme point)成像法由于在深度加权函数中考虑了构造指数,使得成像结果更为准确。笔者基于DEXP快速成像法的基本理论,首先,推导了重力异常及重力梯度张量的DEXP变换形式,并将其应用到场源解释之中;然后,采用理论模型试验,分别分析了数据的点距、误差、计算范围以及背景场对成像结果的影响;最后,将该成像方法应用于实测的全张量重力梯度数据,并与前人研究结果进行了对比与分析。理论模型试验与实际应用均表明:DEXP成像法能够有效压制数据噪声的影响,具有计算稳定性和准确性特点;数据的点距、计算范围和背景场均对DEXP成像结果具有一定的影响,因此在实际数据处理时,应该综合考虑它们对成像结果的影响,并且需要进行相关数据预处理以提高定量解释的精度。Fast imaging inversion method has been a hotspot in quantitative interpretation of gravity and magnetic exploration in recent years.Because it does not need to add prior information in the calculation,it can quickly estimate the source depth,density and other related parameters.DEXP(Depth from Extreme point)imaging method adds the corresponding structural index to the depth scaling function in the calculation,making the imaging results more accurate.Based on the basic theory of the DEXP rapid imaging method,firstly,transformation formulas for gravity field and gravity gradient tensor regarding depth from the extreme point method were calculated and applied to the causative source interpretation in this paper.Then,through different synthetic models tests,the effects of sampling interval,data error,computing range and background field on the imaging results were analyzed,respectively.Finally,the imaging method was applied to the full gravity tensor gradient field data,and the results were compared with those provided by previous researchers in the literature.Both the synthetic tests and the field example show that the DEXP imaging method not only has good suppression on the noise in the observation data but also shows the characteristics of computing stability and accuracy.In addition,the data sampling interval,calculation range and background field all have certain influences on DEXP imaging results.Therefore,when actual field data are interpreted,it is necessary to comprehensively consider their influences on the imaging results and perform the corresponding pre-processing to improve the accuracy of the quantitative interpretation.

关 键 词：DEXP 重力异常 重力梯度张量 定量解释 影响因素分析 

分 类 号：P631[天文地球—地质矿产勘探]